The city of San Francisco is cracking down on Airbnb landlords with a new short-term rentals department.

Mayor Ed Lee was scheduled to announce the brand new Office of Short Term Rental Administration and Enforcement on Thursday, the San Francisco Chronicle reports. The team of six will be in charge of handling the registration of landlords and investigating violations.

While cities all around the worldstruggle with how to keep people from abusing platforms like Airbnb, San Francisco is the first to create a separate department specifically for handling short-term rentals, says Tony Winnicker, a senior adviser to the mayor.

Short-term rentals, which are defined as stays of less than 30 nights, were illegal in San Francisco for decades. However, the ban was rarely enforced until February, when the city legalized the practice, but only under certain conditions. Under the new law, hosts must be permanent residents and are required to obtain a business license, register with the Planning Department, pay a hotel tax, and occupy the property when not renting it out for at least 60 consecutive days. They are also required to keep rental records to show they aren't violating any rules.

Only about 700 hosts out of the more than 5,000 San Francisco listings on Airbnb have registered since February, leading city officials to create the short-term rentals office to more strictly enforce these regulations.

Violation letters have already been sent to 15 Airbnb hosts for allegedly turning 73 residential units into full-time hotels.

Airbnb, a startup that allows people around the world to rent out spare rooms or entire housing units to strangers for a short period of time, is valued at $25 billion and facilitates around one million guest-host arrangements per month, according to co-founder Brian Chesky. The popularity of the service has become an issue in recent years in cities like San Francisco, where rent costs are quickly rising amid a housing shortage and many tenants and landlords are using Airbnb to make some extra money.

Apart from being economically problematic, the constant presence of short-term renters can also be personally disruptive to permanent residents living nearby.

“Airbnb has replaced our quiet environment with noise, anxiety and the nuisance of a steady flow of transients who have no investment in living here,” Daniel Moore of Berkeley, Calif., wrote in a letter to the City Council and the Berkeley Rent Stabilization Board in May.

Some opponents of Airbnb say the recent measures don't go far enough in managing violations. Dale Carlson is one leader of the ShareBetter SF group, which plans to file signatures on Monday to qualify a ballot initiative for the fall asking voters to drastically curb vacation rentals and impose steep fines on platforms like Airbnb for violations. Carlson told the Chronicle he is glad the city “is finally taking some actions” against those in violation of the rules, but pointed out that it will be impossible to detect all offenders due to a lack of data.

“You cannot enforce this law or any other law about short-term rentals unless you have two things: data on the number of nights a place is rented and the ability to go after hosting platforms that list illegal units,” he said. Airbnb and other short-term rental companies have refused to turn over this information to the city.

Zoning Administrator Scott Sanchez acknowledged the challenges in enforcing the new laws and said that for now, the city is catching violators by investigating complaints from neighbors.